Yes, I think it's enough. I don't have a WP8 device with 8 GB of storage but I assume there should be at least 6 GB free for apps. If you install 6 GB worth of apps, then I doubt you'd use all of those apps. For most people, 6 GB is enough room for apps, pictures, and music. If you need more storage for multimedia, then use an SD card.

Games tend to take up the most space so if you play a lot of them then it could fill up fast but for normal non-nav apps the sizes are small from what I've seen. I'd still suggest 16GB though but even on my 8X with no microSD slot I've got a bit over 4GB free right now with Other taking up 2.2GB which should clean up once we get the GDR2 update that let's you manually delete temp files.

8GB is only enough if you have a microSD. I'm having a tough time keeping more then 2GB free on my 32GB SD card LOL.

I don't think there is any 8GB WP8 device without a microSD slot iirc, so that's something. Seeing how you can reinstall things you got as needed, if it's really a problem you can uninstall and then reinstall as needed. Problem with that is you lose your progress in games etc.

That said we are now starting to get games on WP8 and Windows 8 that let's you pick up and play between the two as you choose, pause on Win8 and resume on the phone etc.

On one hand the 920 has 32gb of internal storage but no microD slot which the 820 does have. The 920 has the better camera and higher res screen as well. The 820 is overall smaller and lighter etc. I'd say if you don't care about the camera and the HD screen then save your money and get the 820.